SUMMARY AND DISCUSSION / QUESTIONS

Practice guidelines represent an important knowledge resource for diminishing inappropriate practice variation. But most guidelines are developed for the management of a single disease, rather than for people with several diseases. Combining such guideline recommendations sometimes leads to conflicting recommendations for care. Clinical trials, which serve as the highest quality evidence sources for practice guidelines often eliminate multiple morbidity patients. Might large clinical databases that include information about patients with multiple morbidities over time serve as a preferable knowledge source for developing practice guidelines?